How to play
The Sudoku puzzles here use two techniques. Learn them below, then explore the Mosaic and Balance examples.
Rules
A puzzle is a 9×9 grid split into nine 3×3 boxes. Some cells start with numbers that cannot be changed. Fill the rest with digits 1–9 so that no digit repeats in any row, column or box. Every daily puzzle here has exactly one solution.
Hints in three steps
A hint first shows where to look, then the reason with exact cells, and only then offers to enter the value. Hints are worked out from the numbers currently on the board. If your entries conflict or leave no solution, the hint asks you to review or undo instead of guessing which cell is wrong.
- Show areaWhich row, column or box to look at.
- Show reasonThe exact numbers that rule the other cells out, drawn as lines on the board.
- Apply valueThe number goes in only when you choose to.
Hidden single
Pick one digit and one row, column or box. If every other open cell in that area is blocked because the same digit already sits in its row, column or box, the digit must go in the one remaining cell. For example, if a row is missing 7 and each of its other open cells already sees a 7 in its column or box, the 7 belongs in the last open cell.
Your turn
Naked single
Look at one cell. If eight different digits already appear in its row, column and box combined, only the ninth digit can go there.
Your turn
Entering numbers
Select a cell, then tap a number or press 1–9. Turn on Notes to mark possible digits in small type; notes are only for you and never decide a hint. Erase clears the selected cell, and Undo reverses your last change, including an applied hint.
Keyboard: arrow keys move, 1–9 enter, Backspace or Delete erases, N toggles notes, Ctrl+Z undoes.
Some positions need other techniques. Every daily puzzle here is checked in advance so that it can be finished with these two techniques alone, without guessing. If your own entries lead somewhere these techniques cannot continue, the hint says so instead of revealing an answer.
Saving and time
Progress is saved only in this browser, separately for each puzzle and shared across languages. Active time counts only while the puzzle is on screen and not paused. A new daily puzzle appears at 00:00 UTC; a puzzle you already have open stays as it is.